Adding amp toggle for keysends

[deregs]

Description

Relates to issue: ZEUS-832

Previously, for LND 0.13 and 0.14 nodes, the keysend page would default to sending an amp payment. This could potentially cause issues, because amp payments will fail unless they're being sent to another LND 0.13 / 0.14 node with accept-amp turned on.

This change introduces an amp toggle for keysends. The toggle will only appear if the node supports amp (meaning it's an LND 0.13 / 0.14 node).

Screenshot when toggle is disabling amp payment:

Screenshot when toggle is enabling amp payment:

[kaloudis]

I think the toggle should stay above the Max parts field. Thoughts @Bosch-0?

At the very least it should be consistent with the PaymentRequest view

[deregs]

I think the toggle should stay above the Max parts field. Thoughts @Bosch-0?

At the very least it should be consistent with the PaymentRequest view

I agree, to remain consistent with PaymentRequest, and also users might toggle it on just to see what it is, and then they'd have to scroll all the way down to toggle it off. I made the change, and here's a screenshot for when toggle is enabling amp payment: